 Take the cstrike folder and stick it in the counter-strike source folder. 

Valve\Steam\SteamApps\*accountname*\counter-strike source\

When the window comes up asking you: 

"this folder already contains a folder named cstrike. 
If the files in the existing folder have the same name as files in the folder 
you are moving or copying, they will be replaced. Do you still want to move or
 copy the folder?" and the buttons that say  "Yes"  "Yes to all" "No " and  "Cancel".

Click on "yes to all"

 If none of this happens, then you are doing something wrong. I can't make it any clearer
than that.

blueguile

blueguile@msn.com